Type i hit, also known as heparin associated thrombocytopenia hat, is a nonimmunologic response to heparin therapy, while type ii hit is an immunologic response to heparin therapy. After eliminating the more common etiologies, druginduced thrombocytopenia ditp should be considered as an often overlooked yet easily. Thrombocytopenia presenting after 72 hours of age is usually secondary to. Dager, in chemistry and biology of heparin and heparan sulfate, 2005. In a recent article and in correspondence in the journal it is argued that the large platelet is a young platelet which progresses with age to a smaller, lighter platelet. Hit may affect up to 5% of the patients receiving unfractionated heparin ufh, but an accurate estimate is complicated by diagnostic difficulty. Heparininduced anaphylactoid reaction associated with heparininduced thrombocytopenia in the ed. Heparininduced thrombocytopenia investigations bmj. Heparin induced thrombocytopenia hit can be defined as any clinical event best explained by platelet factor 4 pf4. In this case report, we described a 65year old male patient with hit ii after coronary artery bypass grafting. The mechanism behind drug induced thrombocytopenia is either a decrease in platelet production bone marrow toxicity. Drugs can cause thrombocytopenia by several mechanisms including direct bone marrow or other organ toxicity. Drug induced thrombocytopenia occurs when certain drugs or medications destroy platelets or interfere with the bodys ability to make enough of them. The nurse should teach the patient that the threat for thrombolytic problems will likely end at which time.
Druginduced thrombocytopenia occurs when certain medicines destroy platelets or interfere with the bodys ability to make enough of them. Thrombocytopenia presenting in the first 72 hours of life is usually secondary to placental insufficiency and caused by reduced platelet production. The medical team suspects heparininduced thrombocytopenia hit and discontinues the heparin therapy. Heparin induced thrombocytopenia is an antibodymediated adverse drug reaction to heparin therapy with potentially lifethreatening complications. Hit is considered to be the most important and most frequent druginduced type of thrombocytopenia. Ditp typically appears suddenly, is often severe, and can cause major bleeding and death. Results of the third us national health and nutrition examination survey nhanes iii support the traditional value of 150.
The dif ferential diagnosis of thrombocytopenia and the potential secondary causes of itp are outlined. Heparininduced thrombocytopenia deranged physiology. Heparininduced thrombocytopenia hit is a prothrombotic complication mediated by auto antibodies against heparinplatelet complexes. A nurse collects a urine sample from a patient admitted with possible hemolytic anemia. Heparininduced thrombocytopenia hit is a lifethreatening complication of exposure to heparin eg, unfractionated heparin, low molecular weight lmw heparin that occurs in a small percentage of patients exposed, regardless of the dose, schedule, or route of administration. Heparin induced thrombocytopenia heparininduced thrombocytopenia hit can be defined as a decrease in platelet count that can occur during or shortly after exposure to heparin. This algorithm has been developed for md anderson using a multidisciplinary approach considering circumstances particular to md andersons specific patient population, services. May 03, 2012 heparin induced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. Risk for heparin induced thrombocytopenia with unfractionated and lowmolecularweight heparin thromboprophylaxis. Although it occurs more often than drug induced anemia it is less well understood because techniques for studying drugplateletimmune interactions have been unavailable until recently. Hit often leads to thrombosis in large veins and arteries. Thrombocytopenia is the most common event in hit and occurs in at least 90% of patients, depending. Antithrombotic therapy is required to manage heparin induced thrombocytopenia hitbut currently approved agents such as argatroban must be given parenterally and closely monitored. Heparin induced thrombocytopenia is a serious immunemediated, drug adverse effect.
Heparin induced thrombocytopenia heparin induced thrombocytopenia hit can be defined as a decrease in platelet count that can occur during or shortly after exposure to heparin. There are two types of druginduced thrombocytopenia. After eliminating the more common etiologies, drug induced thrombocytopenia ditp should be considered as an often overlooked yet easily reversible cause of. Riia thrombocytopenia high risk of thrombosis occurs in 50% of untreated cases may be venous dvt, pe or arterial limb ischemia, stroke, mi thrombotic complications can be fatal. Heparin induced thrombocytopenia nejm pdf antiplatelet factor 4heparin antibodies present a major risk of heparin induced thrombocytopenia hit. This article discusses the pathogenesis, diagnosis, and treatment of patients with heparin induced thrombocytopenia. Risk for heparininduced thrombocytopenia with unfractionated and lowmolecularweight heparin thromboprophylaxis. This is the case of a patient with heparin induced thrombocytopenia hit, a syndrome that can be potentially fatal. Thrombocytopenia nejm this condition to pimples blackheads and who could administer the right medical research studies. First, heparin is a widely used anticoagulant see chapter 149.
Hit is usually an immune response which typically occurs 410 days after exposure to heparin. This algorithm has been developed for md anderson using a multidisciplinary approach considering circumstances particular to md andersons specific patient population, services and structure, and clinical information. Heparin induced thrombocytopenia hit immune complexes heparinpf4igg cause platelet activation via the platelet fc. The new england journal of medicine nejm publishes. In conjunction with this change, new guidelines for management of suspected hit. Management of immune thrombocytopenia ou health sciences. Thrombocytopenia associated with heparin due to heparin pf4 antibodies is referred to as heparin induced thrombocytopenia hit. The 4ts score is commonly used as it is the most evaluated tool to date. Although it occurs more often than druginduced anemia it is less well understood because techniques for studying drugplateletimmune interactions have been unavailable until recently. Heparin induced thrombocytopenia hit is considered the most common form of drug induced thrombocytopenia as well as one of the common causes of thrombocytopenia in hospitalized patients. Heparin induced thrombocytopenia hit treatment page 1. A severe drug reaction to heparin that can lead to life and limbthreatening venous andor arterial thromboembolism.
Heparininduced thrombocytopenia hit is an adverse reaction to the drug heparin resulting in an abnormally low amount of platelets thrombocytopenia. Neonatal thrombocytopenia is a common clinical problem. Research over the last 20 years has vastly expanded knowledge, awareness and management of this condition. Heparininduced thrombocytopenia history and exam bmj. Druginduced thrombocytopenia ditp, which also includes thrombocytopenia induced by beverages, foods, and herbal remedies, is an important clinical problem for hematologists.
Heparininduced thrombocytopenia hit is an immunemediated adverse drug reaction that is caused by heparindependent, plateletactivating igg antibodies that recognize complexes of platelet factor 4 pf4 bound to heparin. Heparininduced thrombocytopenia has appeared several times in the cicm fellowship exam, both in the written paper question 9. This can occur due to certain disease processes such as alterations in the immune system or with leukemia. Heparin induced thrombocytopenia hit is an antibody mediated adverse effect of heparin therapy which is classified into two subtypes, hit i which is nonimmune, spontaneously reversible thrombocytopenia and. For instance dietary fat surplus and alcoholic beverages does not count. Drug induced immune thrombocytopenia medication list about thrombocytopenia drug induced. From 1981 to 1991, heparin induced thrombocytopenia was diagnosed in 82 of 4,261 open heart surgical patients 1. Heparininduced thrombocytopenia rn continued education. Evidencebased guidelines for managing patients with immune thrombocytopenia itp were last presented by.
Heparininduced thrombocytopenia 0 drugs learn more about thrombocytopenia drug induced. Thrombocytopenia is a serious condition in which patients have a low platelet count. Heparininduced thrombocytopenia is a serious immunemediated, drug adverse effect. Druginduced thrombocytopenia occurs when certain drugs or medications destroy platelets or interfere with the bodys ability to make enough of them. New guidelines for heparininduced thrombocytopenia. Type i is characterized by a mild thrombocytopenia of early onset which requires careful monitoring but usually not the cessation of heparin therapy. Its diagnosis is based on a medical condition compatible with this syndrome and. This is the case with heparin induced thrombocytopenia, or hit. Heparin induced thrombocytopenia hit treatment page 1 of 7. Hit is considered to be the most important and most frequent drug induced type of thrombocytopenia. Heparininduced thrombocytopenia hit may develop in two distinct forms, type i and type ii see table 1. This is the case with heparininduced thrombocytopenia, or hit.
Clinical features of heparininduced thrombocytopenia including risk factors for thrombosis. Heparin induced anaphylactoid reaction associated with heparin induced thrombocytopenia in the ed. This article discusses the pathogenesis, diagnosis, and treatment of patients with heparininduced thrombocytopenia. Heparin induced thrombocytopenia hit may develop in two distinct forms, type i and type ii see table 1. Heparin induced thrombocytopenia hit is an immunemediated adverse drug reaction that is caused by heparin dependent, plateletactivating igg antibodies that recognize complexes of platelet factor 4 pf4 bound to heparin.
Thrombocytopenia with subacute bacterial endocarditis nejm. N engl j med dec at 23 years of followup, life expectancy was nearly 3 years longer with prostatectomy than with watchful waiting. Two types of heparininduced thrombocytopenia with a distinct aetiology have been recognized. New guidelines for heparin induced thrombocytopenia on september 3, 20 uwmedicine laboratory services released a new reflexive panel for hit antibody testing. Heparininduced thrombocytopenia is an antibodymediated adverse drug reaction to heparin therapy with potentially lifethreatening complications. Heparininduced thrombocytopenia genetic and rare diseases.
Heparininduced thrombocytopenia hit immune complexes heparinpf4igg cause platelet activation via the platelet fc. Diagnosis requires the combination of a compatible clinical picture and laboratory confirmation of the presence of heparin dependent plateletactivating hit antibodies. Heparininduced thrombocytopenia article nursingcenter. Dec 11, 2018 hit heparin induced thrombocytopenia is caused by the body forming antibodies to heparin when it is bound to platelet factor4 pf4 a protein in the blood.
Thrombocytopenia presenting after 72 hours of age is usually secondary to sepsis or necrotising enterocolitis and is. Type i hit, also known as heparinassociated thrombocytopenia hat, is a nonimmunologic response to heparin therapy, while type ii hit is an immunologic response to heparin therapy. Eptifibatideinduced acute profound thrombocytopenia. Clinical and laboratory diagnosis of heparininduced. The treatment of anemia associated with chronic kidney disease remains a serious need in china, with limited access to anemia therapy and. The mechanisms by which drugs cause thrombocytopenia are varied.
This is the case of a patient with heparininduced thrombocytopenia hit, a syndrome that can be potentially fatal. Evaluation of pretest clinical score 4 ts for the diagnosis of heparininduced thrombocytopenia in two clinical settings. New guidelines for heparininduced thrombocytopenia on september 3, 20 uwmedicine laboratory services released a new reflexive panel for hit antibody testing. Correspondence from the new england journal of medicine thrombocytopenia with subacute bacterial endocarditis. Heparin induced thrombocytopenia has appeared several times in the cicm fellowship exam, both in the written paper question 9. Thrombocytopenia is the most common coagulation problem in icu patients and is an independent predictor of death among critically ill patients.
Jan 01, 2010 heparin induced thrombocytopenia hit overview hit i appears to be a benign reaction to heparin beginning 14 days into therapy with a transient mild thrombocytopenia 100 150 x 10. Heparininduced thrombocytopenia in open heart surgical. Heparininduced thrombocytopenia hit is considered the most common form of druginduced thrombocytopenia as well as one of the common causes of thrombocytopenia in hospitalized patients. The mechanism behind druginduced thrombocytopenia is either a decrease in. Key clinical pointsheparin induced thrombocytopenia heparin induced thrombocytopenia hit is characterized by a decrease in the platelet count of more than 50% from the highest platelet count valu. Pf4heparin antibody testing and treatment of heparininduced thrombocytopenia in the intensive care unit. In view of this, it has been apportioned its own revision chapter. Many of the cytotoxic drugs used for cancer chemotherapy and other. How to approach thrombocytopenia hematology american. Hit heparin induced thrombocytopenia is caused by the body forming antibodies to heparin when it is bound to platelet factor4 pf4 a protein in the blood.
However, not all thrombocytopenia is due to such system alterations. Nonheparin anticoagulants for heparininduced thrombocytopenia. Bone marrow suppression or increased peripheral destruction of platelets could be involved. Heparin induced thrombocytopenia hit is a lifethreatening complication of exposure to heparin eg, unfractionated heparin, low molecular weight lmw heparin that occurs in a small percentage of patients exposed, regardless of the dose, schedule, or route of administration. It causes prolonged morbidity, is fatal in 5%10% of cases and causes lifelong disability in another 10% of cases1. Two types of heparin induced thrombocytopenia with a distinct aetiology have been recognized. Hit ii which is an autoimmunemediated adverse effect of heparin therapy. Thrombocytopenia presenting after 72 hours of age is. From 1981 to 1991, heparininduced thrombocytopenia was diagnosed in 82 of 4,261 open heart surgical patients 1. Drug induced thrombocytopenia occurs when certain medicines destroy platelets or interfere with the bodys ability to make enough of them. Thrombosis precedes thrombocytopenia in approximately 25% of patients with hit.
Heparin induced thrombocytopenia hit is an unusual immunemediated adverse drug reaction with the central paradox being its strong association with thrombosis, despite the role of an anticoagulant heparin in causing a fall in platelet count thrombocytopenia. Managing immune thrombocytopenia nejm journal watch. Thrombocytopenia can have several causes, including the use of certain drugs. The differential diagnosis of acute thrombocytopenia in an icu patient is extensive. Hit results from an autoantibody directed against endogenous. Heparininduced thrombocytopenia investigations bmj best. Riia on the platelet surface, platelets become activated, microparticles are released, and the coagulation cascade is triggered. A number of clinical prediction tools have been developed to help physicians determine clinical probability of hit. In some cases, the thrombocytopenia is also immunemediated. These antibodies bind to the combination of heparin and pf4 and activate platelets which in turn clump together and cause small clots in the blood stream and the platelet count falls. Heparin induced thrombocytopenia hit treatment page 2 of 7 disclaimer.
Drug induced profound thrombocytopenia, a predictor of adverse outcome in patients with acute coronary syndromes, is defined as a decrease in platelet count to below 20,000mm 3 within 24 hours of exposure to the drug and may be associated with the administration of eptifibatide, a glycoprotein antagonist. Second, hit is relatively common, occurring in approximately 1% to 3% of postoperative patients, and 0. If a medicine causes your body to produce antibodies, which seek and destroy your platelets, the condition is called druginduced. Heparininduced thrombocytopenia hit is the most important druginduced immunemediated cytopenia for several reasons. Unexplained thrombocytopenia is a common clinical problem, and the possibility of druginduced thrombocytopenia must be considered, especially in hospitalized patients. Hit is a strong risk factor for venous and arterial thrombosis odds ratio, 20 to 40.